Telephone circuit and transformer therefor



May 30, 1933. FULTON Y 1,911,948

TELEPHONE CIRCUIT AND TRANSFORMER THEREFOR Filed Nov. 5, 1931 INVENTOR El. 3/5 FOZZUWd 6' ATTORN EY Fatented May 30, 1933 V UNITED STA ES PATENT": Fries noL ANn s. FULTON, or nn'rnorr, iuicirennsssisnon so. NATIONAL TIME & srenan CORPORATION, OF DETROIE MICEIGABL A CORPORATION OF MICHIGAN TELEPH NE CIRGUITAND Tnnnsronnr'sn THEREFOR Application filed November 5,1931. Serial" No. 573,118.

. This invention relates to telephone circuits and transformers therefor and the object of the invention is to provide a tele phone circuit including a transformer in which the primary is connected to a source of alternating current supply and the secondary is divided, a portion of thesecondary carrying alternating current for thetelephone ringing circuit and the other por tion of the secondary being connected through rectifiers to provide direct current for a. telephone speaking circuit. 7

Another object of the invention is to provide a transformer in which both alternating and direct current are producedjfrom the secondary for operating theringing circuit and speaking circuit of a telephone system. e

Another object ofthe invention is to providea transformer adapted for connection to an A.VC. in-put. and having the out-put connected to providealternating current for telephone bell ringing and direct current fora telephone speaking circuit, the direct current being produced from thealternating .current by rectifying the alternating .CLIT- rentwave. p c z Another object of the invention is to provide a complete instrument for producing two types of current from the same alternating current source.

These'objects and the several novel features of the invention are hereinaftermore fully described and claimed and the pre ferred form of construction by which these objects are attained is shown in the accompanying drawing in which Fig. 1 isa view showing a transformer circuit tion.

Fig. 2 is a perspective view of the casing containing the transformer and. rectifier units. Fig. 3 is a section taken on line A-A of Fig. 2. V v

As shown in Fig. 1 the alternating input circuit is represented by the wires 1 and 2. A fuse 3 is connected in the wire 1 and this wire is provided with a terminal 4. The wire 2 is provided with a switch 5 and this embodyingv my invendiagrammatic I wire is connected to one end of the primary 6 of the transformer. This primary is provided withleads to contact points 7 8 and 9 and a wire 10 connected to the contact 4 may be connected to the contacts 7 8 and 9 to connect more 'or less of the transformer primary into the circuit. The secondary consists of .two parts, a part 11 .in which alternating current'is induced for a telephone bell ringing circuit and parts 12 and g 13 in which alternating current-is induced The part ed to theupper rectifier 14 by thewires and 21. A wire 22. is also provided con necting the :two rectifiers. With this arrangement the two sides of the alternating current wave are carried to the rect'ifiers and the rectifiers are connected inseries across the circuitrepresented by the wires 23 and 24. 7 1 Two choke coils 25 are .connected in the circuit 24E'and a series'of high capacity con densers 26, 27 and 28 are connected across between the circuit wires 23 and 24 and a volt meter 29- is also connected between these wires. This? is'a standard rectifier circuit for transforming alternating current to direct current and the out-put of thiscircuit cuitofa telephone system. :The device is particularly adapted for use with small telephone systems such as the inter-co mmunieating systems utilized in large. factories, manufacturing plants and apartment houses. -"For convenience," the several instrumen; talities are mounted in a compact rectangular casing shown in Figs. 2and 3. The lower' half-ofthe casing contains the high capacity condensers 26, 27 andl28 and :is

provided with a horizontal partition"' rectifiers.

shown in Fig. 3 above the condensers and extending horizontally across the casing.

'Mounted on the partition 30 is the transmagnetic fields. A panel 32 is mounted on the base 30 and carries the fuse 2, switch 5 and volt meter 29 and mounted on the panel 32 above these instruments are the rectifiers 14. nected together in the casing to provide the circuit shown in Fig. 1 and it is only necessary to connect the device to a suitable source of current supply and connect the out-put circuits to the telephone ringing circuit and to the telephone speaking circuit at which time complete current is provided for the entire telephone system.

The primary 6 is tapped as shown in Fig. 1 and the movable circuit wire 10 may be connected to any of these taps 7, 8 or 9. By moving the circuit wire 10 to the various taps the direct current output from the rectifier circuit may be varied'and while this will also vary the out-put for the telephone ringing circuit a slight variation of this out-put circuit will not have a detrimental effect The taps 7, Sand 9 also provide a means for varying the primary accordin'g to the input alternating current voltage. Forinstance,'if the in-putcurrent is 120 volts, the wire 10 may be connected to the tap 7, if the in-put current is 115 volts, the

wire 10 may be connected to the tap 8 and if the in-put current is 110 volts, the ,Wire' 10 may be connected to the tap 9 so as to produce the desired out-put voltage from the It will thus be seen that the tapped primary provides a means for adjusting the primary in accordance with the A. C. input voltage and at the same time if the out-put voltage from therectifiers is too low or too-high the out-put voltage may be varied by connecting the A. G. in-put tothe different taps 7', 8 and 9. Thisarrangement of a tapped'transformer primary to vary the out-put A. G. and D. C. voltage for a telephone circuit is believed to be new and to provide features not heretofore knoWn..fl: f

, From the foregoin'gdescription it becomes evident that the device is very simple and efficient in operation, provides a compact mechanism for inter-communicating telephone systems, is adjustable to vary the output voltage and provides a device which accomplishes the objects described.

'Having' thus. fully described my invention, its. utility and mode of operation, what I claim and'd'esire to secure by Letters Patent of the-United States -is The several instruments are con-" 1. In a telephone circuit, a casing, a parti- I tion mounted intermediate the top and bottom of the casing, a transformer mounted on the partition and having a variable primary adapted to be connected to an alternating current input circuit, the secondary of the transformer being divided and having a portion providing alternating current-for a telephone ringing circuit, a panel mounted on the partition, the casing being provided with an opening through which the panel is exposed to view, a series of rectifiers mounted on the panel, a portion of the secondary being connected to the rectifiers, a series of high capacity condensers mounted in the lower portion of the casing beneath the partition and a series of chokecoils mounted on the partition, the rectifiers being connected to the condensers and choke coils to rectify the transformed current for a telephone speaking circuit and a volt meter mounted on the panel and connected in the telephone ispeaking out-put circuit to give voltage readings thereof.

r 2. In a transformer for use with alternating current to provide alternating current for a telephone ringing circuit and direct .current for a telephone speaking circuit, a

casing, a series of high capacity condensers mounted in the lower portion of the casing,

a horizontal partition intermediate the top and bottom of the casing and providinga cover for the condensers, a transformer mounted on the partition, choke coils mounted on the partition, a verticalpanel mounted on the partition, the casing being provided with an opening adjacent the panel to expose the panel to view, rectifier elements mounted on the panel, a fuse mounted on the panel and connected into the alternating current in-put circuit and a volt 'me-' ter mounted on the panel to give the readings of the telephone speaking out-put circuit.

' 3. 1m a transformer for use with alternating currentto provide currentfor telephone ringing and telephone speaking circuits, a casing, a series of'high' capaoity'condens'ers mounted in the lower portionof the casing,

a horizontal partition extending-across the casing above the condensers, a transformer mounted on the partition, a choke coil mounted on the partition with the core extending at a right angle to the core of the transformer, a panel mounted on the partition, a re'ctifier mounted on'the panel and a volt meter mounted on the panel to give the voltage readings of the telephone speaking out-put circuit. 1

In testimony whereof cation. i

IR LLAND- s. FULTON;

I sign this s pecifi- 1 

